Method for preparing nano attapulgite and phenolic aerogel and method for preparing abrasion-resistant vehicle tire

ABSTRACT

A method for preparing an aerogel comprising nano attapulgite and phenolic aldehyde and a method for preparing abrasion-resistant vehicle tire. 80-100 weight distributions of rubber, 3-8 weight distributions of SiO 2 .nH 2 O, 3-6 weight distributions of an anti-aging agent, 3-4 weight distributions of a heat stabilizer, 3-5 weight distributions of a compatibilizing agent, and 3-12 weight distributions of the aerogel comprising the nano attapulgite and the phenolic aldehyde is selected as a raw material of the abrasion-resistant rubber material to prepare rubber composite material for the abrasion-resistant vehicle tire.

RELATED APPLICATIONS

This application claims priority to Chinese patent application202110186380.2, filed on Feb. 8, 2021. Chinese patent application202110186380.2 is incorporated herein by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates to a technical field of vehicle tirerubber, and in particular relates to a method for preparing an aerogelcomprising nano attapulgite and phenolic aldehyde and a method forpreparing an abrasion-resistant vehicle tire using the aerogelcomprising the nano attapulgite and the phenolic aldehyde.

BACKGROUND OF THE DISCLOSURE

Vehicle tires are essential to modern transportation. Rubber compositematerial is the main component of vehicle tires. Abrasion resistance,flame retardancy, heat dissipation performance, wet skid resistance,energy saving, and environmental protection are all very importantfactors for the rubber.

The development of energy-saving and abrasion-resistant tires is ofvital importance to the tire industry. Since 2012, the fuel efficiencyof automobile tires has been regarded as one of the important indicatorsby EU tire-related regulations. Since the construction of highways inChina in 1988, the scale has developed rapidly. As of the end of 2019,the total mileage of highways reached 149,600 Kilometers and ranks firstin the world. The growth rate of the highways has slowed down in recentyears, which also reflects that the domestic highway construction layoutimproves day by day. Therefore, it is necessary to develop energy-savingand abrasion-resistant tires with high efficiency and flame retardancy.The abrasion resistance and cutting resistance of tires are importantfactors related to the service life of tires and the driving safety ofvehicles. The existing production routes of tire rubber can no longermeet the national requirements for high-performance and safe vehicletire manufacturing. It is necessary to modify the abrasion resistance oftires to obtain tires with good abrasion resistance, strong flameretardancy, and suitability for long-distance and long-termtransportation. In addition, compared to light-duty tires that run onnormal roads, tires that are widely used in mines, construction sites,and heavy-duty loaders have higher requirements for the abrasionresistance and cutting resistance of the carcass material.

Nano attapulgite rustic gel is a kind of nano material with excellentperformance. The higher porosity, expansion volume, and larger specificsurface area of nano attapulgite rustic gel make nano attapulgite rusticgel have better dispersion characteristics than original attapulgitesoil, and the excellent mechanical and thermal properties enable thenano attapulgite rustic gel to be used as a reinforcing material inrubber composite materials. However, the nano attapulgite rustic gel hasstrong hydrophilicity, high surface energy, and is prone to aggregation,which make it difficult to achieve uniform dispersion in rubber andwhich hinders the possibility of improving rubber properties.

BRIEF SUMMARY OF THE DISCLOSURE

An objective of the present disclosure is overcome deficiencies ofexisting techniques and to provide a method for preparing an aerogelcomprising nano attapulgite and phenolic aldehyde.

Another objective of the present disclosure is to provide a method forpreparing an abrasion-resistant rubber using the aerogel comprising thenano attapulgite and the phenolic aldehyde.

Still another objective of the present disclosure is to provide aheavy-duty vehicle tire made of the abrasion-resistant rubber.

A technical solution of the present disclosure is as follows.

A method for preparing an aerogel comprising nano attapulgite andphenolic aldehyde, comprising:

(1) dispersing bisphenol A, tetraethylenepentamine, and paraformaldehydein 1,4-dioxane, stirring in an ice bath for 0.8-1.2 hours, heating toroom temperature, continually stirring for 4-12 hours to obtain amonomer BA-TEPA, wherein a structural formula of the monomer BA-TEPA isas follows:

(2) dispersing original attapulgite in ultrapure water, stirring for0.8-1.2 hours, then adding oxalic acid, hydrothermally processing at120-160° C. for 2-8 hours, then thermally processing at 80-140° C. for10-40 hours to obtain nano attapulgite;

(3) sonicating to disperse the nano attapulgite prepared in step (2) ina 50/50 (vol/vol) water-ethanol solution, then adding chitosan andacetic acid, stirring for 20-25 hours, then adding the monomer BA-TEPAprepared in step (1), stirring, adding formaldehyde, stirring for 2-4minutes, then leaving to stand to form a gel, and finally aging the gelto form a wet gel; and

(4) after substituting the wet gel prepared in step (3) with a solventwith a volume ratio of ethanol and water of 1-3:100 for 3-4 days,freeze-drying to obtain the aerogel comprising the nano attapulgite andthe phenolic aldehyde.

In a preferred embodiment, a ratio of the bisphenol A, thetetraethylenepentamine, the paraformaldehyde, and the 1,4-dioxane is 1mol-4 mol: 1 mol-4 mol: 4 mol-16 mol: 100 mL-500 mL.

In a preferred embodiment, a mass ratio of the original attapulgite andthe ultrapure water is 1:5-1:30, and the adding oxalic acid comprisesadding the oxalic acid to a final concentration of 0.5-5 Mol/L.

In a preferred embodiment, the sonicating to disperse the nanoattapulgite prepared in step (2) in a 50/50 (vol/vol) water-ethanolsolution, then adding chitosan and acetic acid, stirring for 20-25hours, then adding the monomer BA-TEPA prepared in step (1), stirring toeven, then adding formaldehyde, stirring for 2-4 minutes, then leavingto stand to form a gel, and finally aging the gel to form a wet gelcomprises sonicating to disperse the nano attapulgite prepared in step(2) in the 50/50 (vol/vol) water-ethanol solution, then adding 0.05-5 wt% of the chitosan and 0.05-5 volume % of the acetic acid, stirring for20-25 hours, then adding the monomer BA-TEPA prepared in step (1),stirring, adding the formaldehyde, stirring for 2-4 minutes, thenleaving to stand to form the gel, and finally aging the gel at 20-70° C.for 6-30 hours to form the wet gel.

In a preferred embodiment, a mass ratio of the nano attapulgite and themonomer BA-TEPA is 0.05-0.5:0.05-0.5.

In a preferred embodiment, a ratio of the nano attapulgite, thewater-ethanol solution, and the formaldehyde is 0.05 g-0.5 g: 9 mL-11mL: 50 μL-500 μL.

In a preferred embodiment, the aging the gel to form the wet gelcomprises aging the gel at 20-70° C. for 6-30 hours.

Another technical solution of the present disclosure is as follows.

An abrasion-resistant rubber material, wherein a raw material of theabrasion-resistant rubber material comprises the aerogel comprising thenano attapulgite and the phenolic aldehyde prepared by the method.

In a preferred embodiment, the raw material of the abrasion-resistantrubber material comprises 80-100 weight distributions of rubber, 3-8weight distributions of SiO₂.nH₂O, 3-6 weight distributions of ananti-aging agent, 3-4 weight distributions of a heat stabilizer, 3-5weight distributions of a compatibilizing agent, and 3-12 weightdistributions of the aerogel comprising the nano attapulgite and thephenolic aldehyde.

Still another technical solution of the present disclosure is asfollows.

A heavy-duty vehicle tire, wherein the heavy-duty vehicle tire is madeof the raw material comprising the abrasion-resistant rubber material.

The present disclosure has the following advantages.

1. The present disclosure uses nano attapulgite and chitosan astemplates and uses formaldehyde as a crosslinking agent to prepare anaerogel comprising nano attapulgite and phenolic aldehyde, wherein thephenolic aldehyde obtained by ring-opened polymerization in-situ of amonomer BA-TEPA is used as the crosslinking agent to construct aflame-retardant composite aerogel material, a preparation step issimple, an operation of a synthesis method is easy, raw materials arelow-cost and easily obtained, and a reaction condition is easilycontrolled.

2. The aerogel comprising the nano attapulgite and the phenolic aldehydeof the present disclosure has ultra-low density and can effectivelyreduce a weight of rubber composite material. An abrasion resistance ofa vehicle tire is improved, and a flame retardant property of thevehicle tire is also improved at the same time. The aerogel comprisingthe nano attapulgite and the phenolic aldehyde satisfies requirementsfor high performance and safety in vehicle tire manufacturing and isespecially suitable for a heavy-duty vehicle tire that has higherrequirements for abrasion-resistance.

3. The aerogel comprising the nano attapulgite and the phenolic aldehydeof the present disclosure can not only solve an agglomeration problem ofnano attapulgite in the existing techniques, but also a compatibilityand a dispersibility of the nano attapulgite in rubber components areimproved.

4. Compared with phenolic aldehyde and inorganic nano attapulgite, theaerogel comprising the nano attapulgite and the phenolic aldehyde of thepresent disclosure has higher cohesion force for rubber, so a bondingstrength of the aerogel comprising the nano attapulgite and the phenolicaldehyde is much greater than a bonding strength of phenolic aldehydeparticles.

5. After the aerogel comprising the nano attapulgite and the phenolicaldehyde of the present disclosure is formed, the aerogel comprising thenano attapulgite and the phenolic aldehyde can be used as a structuralcomposite material to enhance mechanical properties by combining withorganic polymers, inorganic materials, or metal matrix, and cansynergize a cross-linking effect of the monomer BA-TEPA with the olefinon the rubber, so that a dispersibility of the aerogel comprising thenano attapulgite and the phenolic aldehyde in the rubber is improved.The phenolic aldehyde has good flame-retardant properties andhydrophobicity, and a flame-retardant performance and a wet skidresistance of the rubber can be also improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a proton nuclear magnetic resonance spectrum of aBA-TEPA monomer of Embodiment 1 of the present disclosure.

FIG. 2 illustrates an infrared spectrum of the BA-TEPA monomer ofEmbodiment 1 of the present disclosure.

FIG. 3 illustrates a scanning electron micrograph (SEM) of nanoattapulgite of Embodiment 1 of the present disclosure.

FIG. 4 illustrates stress-strain compression curves of chitosan andphenolic aerogel prepared in a control example 1 and the nanoattapulgite and phenolic aerogel prepared in Embodiment 1 of the presentdisclosure, wherein curve a represents a stress-strain compression curveof the chitosan and the phenolic aerogel prepared in the control example1, and curve b represents a compressive stress-strain curve of the nanoattapulgite and the phenolic aerogel prepared in Embodiment 1.

FIG. 5 illustrates thermogravimetric curves of nano-attapulgite andchitosan aerogel prepared in a control example 2 and the nanoattapulgite and the phenolic aerogel prepared in Embodiment 1 of thepresent disclosure, wherein curve al represents a thermogravimetriccurve of the nano-attapulgite and the chitosan aerogel prepared in thecontrol example 2, and curve b1 represents a thermogravimetric curve ofthe nano attapulgite and the phenolic aerogel prepared in Embodiment 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The technical solution of the present disclosure will be furtherdescribed as follows in combination with the accompanying embodimentsand drawings.

Embodiment 1

(1) Preparation of a monomer BA-TEPA (i.e., phenolic monomerBA-TEPA):bisphenol A, tetraethylenepentamine (TEPA), andparaformaldehyde are dispersed (e.g., dissolved) in 100 mL of1,4-dioxane, mechanically stirred in ice bath for 1 hour, heated to roomtemperature (e.g., 20-25° C.), and continually mechanically stirred for8 hours to obtain a uniform yellow viscous fluid. Referring to FIGS. 1and 2 , which is the monomer BA-TEPA, a structural formula is asfollows:

A dose ratio of the bisphenol A, the tetraethylenepentamine, theparaformaldehyde, and the 1,4-dioxane is 1 mol: 1 mol: 4 mol: 100 mL. Areaction principle in which rubber is modified using the phenolicmonomer BA-TEPA is as follows:

(2) Preparation of nano attapulgite: original attapulgite is dispersedin ultrapure water with a mass ratio of 1:20 and stirred for 1 hour, 1M(mol/L) of oxalic acid is added, hydrothermally processed at 140° C. for6 hours, and then thermally processed at 120° C. for 24 hours or thenthermally processed at 120° C. for 24 hours and washed to neutrality.Referring to FIG. 3 , the nano attapulgite is then obtained.

(3) Preparation of aerogel: 0.25 g of the nano attapulgite is sonicatedto be dispersed in 10 mL of 50/50 (vol/vol) water-ethanol solution, 1 wt% (weight percent) chitosan and 1 volume % (volume percent) acetic acidare added and stirred for 24 hours, 0.05 g of the phenolic monomerBA-TEPA is then added and uniformly stirred, 100 μL of formaldehyde isthen added, stirred for 3 minutes, and then left to stand to form a gel.The gel is finally aged at 60° C. for 8 hours to form a nanoattapulgite-phenolic wet gel.

(4) After the nano attapulgite-phenolic wet gel is substituted with anethanol-water solvent with a volume ratio of 1:100 for 3 days andfreeze-dried at −30° C. to maintain original gel space structure, andthe aerogel comprising the nano attapulgite and the phenolic aldehyde isfinally obtained.

3-12 weight distributions of the aerogel comprising the nano attapulgiteand the phenolic aldehyde prepared in this embodiment, 80-100 weightdistributions of rubber, 3-8 weight distributions of a white carbonblack (SiO₂.nH₂O), 3-6 weight distributions of an anti-aging agent, 3-4weight distributions of a heat stabilizer, and 3-5 weight distributionsof a compatibilizing agent are mixed in an internal mixer, continuallymixed, materials are then discharge to a cutting machine, a sheet isobtained by three processes, which including calendering, extruding, andmolding, an abrasion-resistant rubber material for preparing anabrasion-resistant vehicle tire is obtained, and the abrasion-resistantrubber material defines a certain shape.

Control Example 1

In this control example, a chitosan-phenolic aerogel is prepared. Thiscontrol example differs from Embodiment 1 in that: the step (2) isomitted, and 1 wt % (weight percent) chitosan and 1 volume % (volumepercent) acetic acid are added and stirred for 24 hours. 0.05 g of thephenolic monomer BA-TEPA is then added and well stirred, 100 μL offormaldehyde is added and stirred for 3 minutes and then left to standto form a gel. The gel is finally aged at 60° C. for 8 hours to form achitosan-phenolic wet gel.

A preparation of a rubber material in this control example is the sameas Embodiment 1.

Control Example 2

In this control example, a nano attapulgite-chitosan aerogel isprepared. This control example differs from Embodiment 1 in that: instep (3), 0.25 g of nano attapulgite is sonicated to be dispersed in awater-ethanol solution (V_(H2O)/V_(EtOH)=1:1), 1 wt % (weight percent)chitosan and 1 volume % (volume percent) acetic acid are added andstirred for 24 hours, 100 μL of formaldehyde is then added, stirred for3 minutes, and left to stand to form a gel. The gel is finally aged at60° C. for 8 hours to form a wet gel.

A preparation of a rubber material in this control example is the sameas Embodiment 1.

An abrasion test condition of the abrasion-resistant rubber materialprepared in Embodiment 1 and Control example 2 is as follows: sandpaperwith a thickness of 120 A, a slip velocity of 10 m/min, a slip ratio of5%, a load of 75 N, and a time of 15 minutes. Test data is shown in thefollowing table:

Average abrasion Abrasion weight (g) Specific volume Sample Sample 1Sample 2 Sample 3 Average gravity (cm³) Control 41.4887 − 40.4075 −40.9765 − 0.113 1.126 0.102 example 2 41.3951 = 40.2730 = 40.8654 = 0.0936  0.1345  0.1111 Embodiment 1 41.8475 − 40.9355 − 40.9588 − 0.1001.109 0.089 41.7365 = 40.8265 = 40.8782 =  0.1110  0.1090  0.0806

Referring to FIG. 4 , a curve a and a curve b are respectivelycompressive stress-strain curves of the aerogel comprising the nanoattapulgite and the phenolic aldehyde prepared in Embodiment 1 and thechitosan-phenolic aerogel prepared in Control example 1, which indicatesthat the aerogel comprising the nano attapulgite and the phenolicaldehyde prepared in Embodiment 1 has better mechanical properties.

Referring to FIG. 5 , a curve al and a curve b1 are respectivelythermogravimetric curves of the chitosan-phenolic aerogel prepared inEmbodiment 1 and the nano attapulgite-chitosan aerogel prepared inControl example 2. Carbon-residue contents are respectively 63.4% and43.5%, which indicates that the aerogel comprising the nano attapulgiteand the phenolic aldehyde prepared in Embodiment 1 has a betterflame-retardant effect.

It can be known from the above results that the abrasion-resistantrubber material prepared in the embodiment of the present disclosure canbe used to prepare a heavy-duty vehicle tire.

The aforementioned embodiments are merely some embodiments of thepresent disclosure, and the scope of the disclosure is not limitedthereto. Thus, it is intended that the present disclosure cover anymodifications and variations of the presently presented embodimentsprovided they are made without departing from the appended claims andthe specification of the present disclosure.

What is claimed is:
 1. A method for preparing an aerogel comprising nanoattapulgite and phenolic aldehyde, comprising: (1) dispersing bisphenolA, tetraethylenepentamine, and paraformaldehyde in 1,4-dioxane, stirringin an ice bath for 0.8-1.2 hours, heating to room temperature,continually stirring for 4-12 hours to obtain a monomer BA-TEPA, whereina structural formula of the monomer BA-TEPA is as follows:

(2) dispersing original attapulgite in ultrapure water, stirring for0.8-1.2 hours, then adding oxalic acid, hydrothermally processing at120-160° C. for 2-8 hours, then thermally processing at 80-140° C. for10-40 hours, washing to neutrality to obtain nano attapulgite; (3)sonicating to disperse the nano attapulgite prepared in step (2) in a50/50 (vol/vol) water-ethanol solution, then adding chitosan and aceticacid, stirring for 20-25 hours, then adding the monomer BA-TEPA preparedin step (1), stirring to even, then adding formaldehyde, stirring for2-4 minutes, then leaving to stand to form a gel, and finally aging thegel to form a wet gel; and (4) after substituting the wet gel preparedin step (3) with a solvent with a volume ratio of ethanol and water of1-3:100 for 3-4 days, freeze-drying to obtain the aerogel comprising thenano attapulgite and the phenolic aldehyde.
 2. The method according toclaim 1, wherein a ratio of the bisphenol A, the tetraethylenepentamine,the paraformaldehyde, and the 1,4-dioxane is 1 mol-4 mol: 1 mol-4 mol: 4mol-16 mol: 100 mL-500 mL.
 3. The method according to claim 1, wherein:a mass ratio of the original attapulgite and the ultrapure water is 1:5to 1:30, and the adding oxalic acid comprises adding the oxalic acid toa final concentration of 0.5-5 Mol/L.
 4. The method according to claim1, wherein a mass ratio of the nano attapulgite and the monomer BA-TEPAis 0.05-0.5:0.05-0.5.
 5. The method according to claim 4, wherein aratio of the nano attapulgite, the water-ethanol solution, and theformaldehyde is 0.05 g-0.5 g: 9 mL-11 mL:50μ-500 μL.
 6. The methodaccording to claim 1, wherein the aging the gel to form the wet gelcomprises aging the gel at 20-70° C. for 6-30 hours.